In the production of carbon black it is desirable to control certain output variables of the carbon black in order to produce carbon black of substantially consistent quality. Carbon black output variables that are often the focus of control are the iodine number and the DBP. Because the input variables and other physical parameters of carbon black production processes frequently change while the carbon black is produced, it has proved difficult to produce carbon black of substantially consistent quality. Input variables that frequently fluctuate during the carbon black production process are, for example, the air humidity and the fuel quality. Fluctuations in the input variables can have a significant influence on the carbon black output variables, such as iodine number and/or DBP. Likewise, other unmeasurable physical parameters frequently change during the carbon black production process, and also affect the carbon black output variables, such as iodine number and/or DBP.
In some known carbon black production systems, samples of the carbon black produced are taken at spaced intervals, for example, once every few hours of operation. Then, the output variables, such as iodine number and/or DBP, are measured for each sample. The operator then adjusts one or more input variables, such as the feedstock flow rate, after each sample is tested. The operator's adjustment is usually based on his or her own subjective experience with the particular carbon black production system, in order to try and bring the output variables, such as iodine number and/or DBP, back toward their goal values.
One problem with such known methods of controlling the production of carbon black is that the carbon black output variables, such as iodine number and/or DBP, are not controlled during the time intervals between samples. Therefore, if changes in the input variables or other physical parameters of the carbon black production system cause the value of the output variables, such as iodine number and/or DBP, to move outside of a desirable range of values, the change usually will not be noticed until the next sample is taken. As a result, a substantial amount of the carbon black produced may not fall within the customer's specifications. Yet another problem with such known methods of controlling the production of carbon black, is that such methods rely on the subjective analysis of the operator in order to adjust one or more input variables, based on the values of the laboratory measured output variables. As a result, input variable adjustments frequently may vary between operators and, therefore, result in an inconsistent quality in the carbon black produced.
It is an object of the present invention, therefore, to overcome the problems and disadvantages of known carbon black production systems.